1. Field
The present disclosure relates generally to management of an electric power system. More specifically, the present disclosure relates to a system used for preventing switching errors in an electric power system.
2. Related Art
In complex electric power plants or transmission substations, where various types of equipment are operating at high voltages, switching errors can lead to disastrous outcomes, such as interruptions of power, damages to equipment, and loss of human life. A number of factors can cause switching errors, including equipment failure, faults of the control system, human error, and inadequate interlocking devices. Statistics have shown that most switching errors are caused by human error, which can be prevented with proper interlocking design.
Common switching errors include energizing a grounded line, closing a ground switch when energized, de-energizing or load dropping using a disconnector instead of a breaker, or entering an energized switching bay. In order to prevent these switching errors, it is essential to ensure that the correct switching sequence is followed by the switching personnel. In addition, the switching personnel must be fully aware of the impact of each switching step and have the assurance that the next step is proven safe before the actual switching takes place. This requires a simulation system that models the connectivity of a substation and the interlocking logic among the switching operations. Before operating on a piece of equipment, a worker is required to perform a switching-sequence simulation, which verifies whether the sequence of operations complies with safety rules and regulations. If an operation step violates a safety rule, the simulation system notifies the worker such operation cannot proceed.
Conventional switching-sequence simulation systems rely on human programmers to generate and input logic expressions that describe operation of the equipment, which can require a huge amount of work for a large-scale, complex power system, and thus is prone to unintended omissions or typographical errors. In addition, operation of certain complex equipment (such as a bridge transformer) may involve complex logic, making it difficult to summarize all possible operating modes.